Showing papers by "Valerian Dragutan published in 2016"

Cooperative effects of lanthanides when associated with palladium in novel, 3D Pd/Ln coordination polymers. Sustainable applications as water-stable, heterogeneous catalysts in carbon–carbon cross-coupling reactions

Abstract: Three novel porous heterobimetallic coordination polymers, [Ln2Pd3(BPDC)2(HBPDC)2(μ2-O)Cl4(H2O)6·nH2O]m (Ln = Pr, n = 5 (1), Ln = Gd, n = 4 (2), and Ln = Tb, n = 4 (3)), were readily prepared by combining Pd(II) and Ln(III) with 2,2′-bipyridine-4,4′-dicarboxylic acid (H2BPDC) as a heteroleptic ligand, under hydrothermal conditions, and structurally characterized by means of single-crystal X-ray diffraction, FT-IR, powder X-ray diffraction, elemental analysis and thermogravimetric (TG) techniques. Single-crystal X-ray diffraction examination showed that 1–3 have similar 3D frameworks, connected via hydrogen bonding interactions, and consisting of three distinct types of building blocks: Pd(BPDC)Cl2, Pd(HBPDC)2 and a Ln dimer (Ln2O15). The new isostructural, air and water stable coordination polymers, resulting from association of lanthanides with palladium, exhibited superior but distinct capabilities as eco-friendly heterogeneous catalysts in Suzuki-Miyaura, Heck and Sonogashira cross-couplings, under green reaction conditions. Supramolecular, solid catalysts 1–3 have been recovered quantitatively from the reaction mixtures by simple filtration. Also importantly, their sustainability, utility and cost-effectiveness have been demonstrated by recycling experiments with catalyst 1 in Suzuki-Miyaura, proceeding practically without loss of activity after four runs.

The synergistic effect of cobalt on a Pd/Co catalyzed Suzuki–Miyaura cross-coupling in water

Abstract: This work introduces the new trimetallic complex CoPd2(HBPDC)2Cl4·(H2O)4(H2BPDC = 2,2′-bipyridine-4,4′-dicarboxylic acid) as a highly efficient and more cost-effective catalyst for a Suzuki–Miyaura reaction proceeding in water, without additives and under aerobic conditions. Catalytic studies revealed a synergistic Co–Pd cooperativity, fostered by ligation through H2BPDC, and accounting for the superior performance of the heterobimetallic complex vs. its Co-free counterpart.

ROMP Synthesis of Iron-Containing Organometallic Polymers.

Abstract: The paper overviews iron-containing polymers prepared by controlled "living" ring-opening metathesis polymerization (ROMP). Developments in the design and synthesis of this class of organometallic polymers are highlighted, pinpointing methodologies and newest trends in advanced applications of hybrid materials based on polymers functionalized with iron motifs.

Recent Advances in Metathesis-Derived Polymers Containing Transition Metals in the Side Chain

Abstract: This account critically surveys the field of side-chain transition metal-containing polymers as prepared by controlled living ring-opening metathesis polymerization (ROMP) of the respective metal-incorporating monomers. Ferrocene- and other metallocene-modified polymers, macromolecules including metal-carbonyl complexes, polymers tethering early or late transition metal complexes, etc. are herein discussed. Recent advances in the design and syntheses reported mainly during the last three years are highlighted, with special emphasis on new trends for superior applications of these hybrid materials.